flu in 4 month old?

Hello everyone! I have never posted on here before but I have posted on this website many times. I have a question for all you experienced moms. Can my 4 month old get the flu? This morning he threw up, not just spit up it was accual heaving and puking. I am thinking he is starting to teeth, could this be a reason for the throwing up? He dosen't have a fever. I do have two other children but I don't remember them getting sick this soon with the flu. No one else in our family has signs of the flu, pray that they don't! Thanks in advance for any advice. Have a great day and God bless, Penni